Electromagnetic phonographic reproducer



Feb. 5, 1929.

C. F. GOUDY ELECTROMAGNETIC PHONOGRAFHIC REPRODUCER Filed Oct. 5, 1927 INVENTOR ATTORNEY Patented Feb. 5, 1929.

UNITED STATES PATENT OFFICE.

CARL F. GOUDY, F FLUSHING, NEW YORK, ASSIGNOR TO .'PACENT RADIO CORPORA- TION,'OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

.ELECTEOMAGNETIC PHONOGRAPHIC REPRODUCER.

Application led October 5, 1927. Serial No. 224,050.

This invention relates particularly to electromagnetic reproducers of the type disclosed in co-pending patent application, Serial #209,500.

Special objects in this case are to provide a more sensitive action, to obtaingreater energy; to reproduce faithfully without distortion or blast; to construct the apparatus in such a form that the parts may be assembled l0 and properly adjusted without bein subjected to magnetic or other possible dlsturbing iniiuences and in genera-l, to provide a more practical and eiicient form of apparatus than has heretofore been attained.

These and other desirable objects are attained by certain novel features of construction, combinations and relations of parts as set forth in the following s eciication and broadly covered in the appen ed claims.

The drawing accompanying and forming part of the specification illustrates one practical commercial embodiment of the invention, but it should be understood that such disclosure is primarily illustrative in character and that changes and modifications in the structure may be made without departure from the true spirit and broad nature of the invention.

Figure 1 is a side view of the reproducer or pick-up in cooperative relation with a phonograph record, the case of the device appearing in section. i

Figure 2 is a front view of the device removed from its case. Y

Figure 3-is a bottom view of the device.

vFigure 4 is an enlarged sectional View as on substantially the plane of line 4 4 of Figure 1.

The magnetic system of the unit comprises a short but relatively powerful permanent horse-shoe magnet 5 having laminated pole ieces 6 secured to the legs of the same and ormed with polar projections 7 approached to provide a magnetic gap at 8. These polar projections are located up near the arch of the magnet and at their lower ends the pole pieces are shown formed with lesser projections 9 approaching each other across the space between the ends of the ma et. As

s own particularly in Figures 2 an 3, a considerable gap is provided between the rojections 9 to prevent magnetic leakage t erebetween. o j

The pole pieces 6 are secured 1n properly spaced relation by means of avbridge iece 10 to which the lower projections '9 o the pole pieces are secured by means of screws 11 extending through projections 9 into screw seats 12 shown formed as integral screw bushings on said bridge piece.

Also supported by the bridge piece is the coil 13 shown centered in position thereon between the up'per and lower arms 7, 9, of the pole pieces. This coil has terminals 14 on an lnsulating base strip 15 secured by nuts 16 at the back of the magnet, said terminals having the cord conductors 17 connected therewith.

Operating in the magnetic ga between the pole tips 7 is a magnetic reedp or arma.- ture 18 carried by an upstanding arm 19 projecting freely up through the center of the coil. This arm is shown as of cylindrical form so as to lit closely but without contact in the bore of the coil and is further shown as an integral-angularly projecting upward extension on the inner end of a squared bearing portion 20. At the outer end this s uared bearing portion carries `a downwar y di rected angularly extending needle holder 21 provided with a clamp screw 22 and preferably of a size and shape to accommodate various styles of needles such as the usual steel needles or liber needles 23, etc.

The squared base or shank portion 20 of the reed is supported and resiliently heldin a tubular sleeve 24 of rubber or other elastic material clamped in an inverted V-groove 25 provided in the outstanding flange or shelf 26 of the bridge piece by a V-trough clamp plate 27 secured to the shelf of the bracket by small screw bolts 28. The inner end of the clam plate 27 seats in a V slot 29 in the back of t e bracket or bridge piece 10, which .seat as shown in Figure 4 is of wider angle than the V clamp so that said V clamp may have arocking motion therein for the purpose of tilting the squared shank one way or the other to center the. end of the reed between the pole tips.

It will thus be seen that the clamp screws 28 may be set u together to compress the elastic sleeve an thus firmly secure the reed in. lace and may be adjusted one independent y of the other to rock the reed s hghtly one way or `the other and hence bring 1t lnto centered relation in the magnetic gap. l .j The supporting flange26 1s lllustrated m Figure 2 as depressed at 30 on opposlte sldes of the inverted V seat therein to provide recessed seats for the nuts 3l on the upper ends of the clamp screws 28.

With the construction disclosed it is possible to assemble the coil with the pole pieces and the reed on the supporting bracket l0, securing these parts in their proper adjusted relation by means of the screws l2 which d'1- rectly fasten the pole pieces to the bracket and the screws 28 which fasten the reed clamp in place. The screws, 28, furthermore, enable the reed to be centered in the gap between the pole tips so that as shown in Figure Li, these parts may be made up and properly adjusted apart from the permanent magnet and ready 'to go on to the permanent. magnet as a single unit after they have once been so arranged and adjusted.

This pole piece unit, as it may be termed, comprising the pole pieces, coil and reed all secured together in properly adjusted relation, is attached to the permanent magnetin the unitary form described, by means of two screws 32 extending through the bracket lO, the lower end portions of the laminated pole pieces and the arms of the U magnet, the nuts 16 before referred to being engaged on the projecting rear ends of these screws. These same screws are snown utilized in the present illustration for securing the casing 33 in place, cap nuts 34 engaged on the extended ends of said screws serving this latter purpose.

The casing 33 is indicated in Figure l as having a flexible strap or loop 35 at one side of the same which can be contracted by a thumb screw 36 to grip the unit on the end of a phonograph tone arm so that the needle will properly cooperate with the record shown at 37 carried by the usual turn table 88.

The angular or squared shank of the reed clamp diagonally in the elastic sleeve provides in effect a resilient pivot having an axis substantially at a right angle to the lateral traverse of the needle and the movementof the reed between the pole tips. The leverage of the needle and of the reed are therefore both effective in the translation of inechanical vibrations from the record to electrical oscillations in the coil. By varying the length of these levers, the mechanical effect-s of the needle may be increased or decreased as desired.

To facilitate assemblage of the pole pieces on the bracket, the latter is shown in Figures l and 2 as having an inturned flange 39 at its lower edge forming a gage or stop for the lower ends of the pole pieces and serving also as a rib for strengthening and reinforcing the bracket.

In constructing the reed, the upstanding arm portion of the same is preferably hollowed, by drilling or otherwise, as indicated atlQ, to make it as light as possible and the upper end of this liollowed portion is then flattened as indicated in the drawing, to provide a maximum area exposed to the pole pieces. A light, rigid reed is thereby provided and this reed has maximum areas opposed and exposed to the pole pieces of the magnet. Consequently, the action is most sensitive.

l/Vhat is claimed is:

l. An electromagnetic pick-up device comprising a shank having angularly projecting elements at opposite ends of the same, one of said elements providing a magnetic reed and the other a needle holding clamp, a magnet system having a magnetic gap in which the free end of said reed element oseillates, a coil associated with and forming part of said magnet system, and a continuously extending clamp adjustably holding the intermediate portion of said shank between the magnetic reed at one end and the needle clamp at the opposite end of the same.

2. An electromagnetic pick-up device comprising a. magnet having spaced pole pieces, a. coil associated with said magnet, a bracket rigidly attached to said magnet, a reed magnetically related to the pole pieces and having an angularly extending supporting shank and clamping means resiliently securing said shank to the bracket and adjustable to vary the position of the shank and the location of the reed relative to the pole pieces.

3. An electromagnetic piek-up device comprising a bracket, pole pieces secured in proper spaced relation on said bracket, a magnetic reed movably secured on the bracket in proper cooperative relation to said pole pieces, whereby said bracket, pole pieces and reed constitute a single unit structure. a magnet and means for rigidly securing the unit structure aforesaid to said magnet with the pole pieces properly related to the poles of the magnet-and whereby said pole pieces are immovably connected with the permanent magnet and the reed is then movably related to said immovably held pole pieces.

4, An electromagnetic pick-up device comprising a bracket, co-related pole pieces, coil and magnetic reed all mounted on said bracket and held thereby in proper cooperative relation in a single unit structure, a. magnet, means for rigidly securing said unit structure to said magnet with the pole pieces properly co-related to the poles of the magnet and means for adjustably setting the magnetic reed on the bracket in proper cooperating relation to the pole pieces.

5. An electromagnetic device of the character disclosed comprising a U magnet, laminated .pole pieces overlying the legs of said magnet and having cooperating opposed projections aHording a magnetic gap and other opposed projections more widely separated, a bridge piece overlying said latter projections and secured thereto, a coil held between said two sets of projections, an outstanding flange nih carried by said bridge piece, a clamp plate adjustably secured to said flange, a shank element surrounded by a resilient sleeve and secured between said flange and clamp, an arm on the inner end of said shank projecting up through the coil into the magnetic gap, a needle holder on the outer end of said shank and screws fastening the bridge piece and parts attached thereto to the arms of the magnet.

G. In a device of the character disclosed, a U-magnet, a clamp bar for bridging the arms of said magnet, pole pieces secured to said clamp bar and thereby held in predetermined spaced relation, a magnetic reed, a clamp for securing said reed to the clamp bar and adjustable to variably position the reed with respect to the pole pieces and means for fastening the end portions of the clamp bar to the sides of the magnet to rigidly secure the assembly described in position on the magnet.

7. In a device of the character disclosed, a magnet having spaced arms, pole pieces for fiat engagement against the face of said magnet arms, a clamp bar overlying said pole pieces and bridging the space between the arms of the magnet, screws for fastening the pole pieces to the clamp bar in definitely spaced relation, screws for fastening the end portions of the clamp bar to the arms of the magnet, a coil associatedwith the pole pieces, a magnetic reed projecting through said coil, said reed having an armature portion disposed betweenY the pole pieces` and a shaft portion adjacent the clamp bar and screw means for adjustably Securing the shaft portion of said magnetic reed to the clamp bar.

8. In a device of the character disclosed, a magnet having spaced arms, pole pieces overlying the face of said magnet arms, a clamp bar bridging the space between the arms and overlying said pole pieces to secure the same to the magnet, Said clamp bar having an angularly projecting flange, a coil associated with the pole pieces, a magnetic reed extending up through said coil and having uan armature portion disposed between the pole pieces, said reed having a shaft portion eX- tending substantially parallel with the an gularly projecting flange of the bar and means for securing said shaft of the reed to said flange.

9. In a device of the character disclosed, a magnet having spaced arms, pole pieces overlying the face of said magnet arms, -a clamp bar bridging the space between the arms and overlying said pole pieces to secure the same to the magnet, said clamp bar having an angular-ly projecting flange, a coil associated with the pole pieces, a magnetic reed extending up through said coil and having an armature portion disposed between the pole pieces, said reed having a shaft portion extending substantially parallel with the angularly projecting flangel of the bar, means for securing said shaft of the reed to said flange, said reed supporting flange projecting out from the upper edge of the bar and an anglilarly projecting fiange extending inwardly from the lower end of the bar into position beneath the pole pieces.

l0. In a device of the character disclosed, a magnet having spaced arms, pole pieces overlying the face of lsaid magnet arms, a clamp bar bridging the space between the arms and overlying said pole pieces to secure the same t0 the magnet, said clamp bar having an angularly projecting ange, 'a coil associated with the pole pieces, a magnetic reed extending up through said coil and having an armature portion disposed between the pole pieces, said reed having a shaft portion eX- tending substantially parallel with the angularly projecting flange of the bar, means for securing said shaft of the reed to said flange and said clamp bar having an angularly projecting flange additional to said reed mounting flange for reinforcing and rendering the bar rigid to hold the pole pieces firmly engaged with the arms of the magnet.

11. In a device of the character disclosed, a magnet of the U-type, fiat pole pieces in flat engagement with and overlying the arms of the magnet at one face of the magnet, an insulating base overlying the arms at the oppoe site face of the magnet coil, terminals mounted on said insulating base, a bar overlying the pole pieces and clamping the same to the face of the magnet, a coil supported above said overlying bar and connected with the terminals on the insulating base, a magnetic reed havi-ng a mounting portion, a part projecting through the coil and an armature portion in magnetic relation to the pole pieces and means for securing the mounting portion of the reed to the clamp bar independently of the fastening of the clamp bar to the magnet and adjustable to vary the relation of the reed to the pole pieces.

12. In a device of the character disclosed, a magnet structure having spaced pole pieces, a magnetic reed having a mounting shaft and an armature portion extending angularly from said mounting shaft, said armature portion being magnetically related to said pole pieces, a rocking clamp engaged over the mounting shaft for said reed and adjustable to rock said shaft to tiltthearmature portion of the reed toward one or `the other of the pole pieces for accurately centering the armature portion between the pole pieces and a winding associated with said magnetic reed.

13. In a device of the character disclosed, a magnet having pole pieces, a magnetic reed having an armature portion magnetically related to said pole pieces and an angularly related mounting shaft, a clamp. engaging said mounting shaft for supporting the magnetic reed and including screw means by which the clamp may be tipped to tilt the mounting shaft and hence the armature portion of the reed relative to the pole pieces and a magnetizing coil associated with said reed.

14. In a device of the character disclosed, a magnet having pole pieces, a reed having an armature portion associated with said pole pieces and a mounting portion, a bar having a V-sh aped opening for passage of the mounting portion of the reed and a iange above said opening, said flange having a seat for the mounting portion of the reed, a clamp plate sup ported at one end in the edge of said opening, screw means for supporting the opposite end ot said ciamp plate to secure the mounting portion oit the reed to its seat in the flange and a coil associated with the reed.

15. In a. device of the character disclosed, the combination with a magnet structure ifonooo having spaced pole pieces, of a magnetic reed having an armature portion positionedin the gap between the pole pieces, said magnetic reed having a shaft portion angularly related to the armature portion, a supporting member having a seat for said shaft portion, a clamp plate overlying said shaft ortion and holding the same to the seat oio the support and screws acting on said clamp plate at opposite sides of the shaft portion to thereby tiltably secure said clamp plate in position, so that by tilting adjustments of said clamp plate the shaft portion may be rocked one Way or the other to center the armature portion in the magnetic gap aforesaid.

In testimony whereof I aiiix my signature.

CARL F. GOUlDY. 

